Powerline communication (PLC) might have interferences to fixed radio broadcasting or other external transmissions. Today, PLC modems have fixed notch filters for amateur radio bands. Filters for fixed notches can be implemented with a high suppression and very steep slopes. Concepts of dynamic or smart notching enables PLC modems to detect an ingress of fixed radio broadcast stations. The frequencies where radio stations have been detected shall be omitted by PLC. In order to realize this in a PLC transmitter, adaptive notch filters for suppressing a transmission signal in a predetermined frequency band might be used. These adaptive notch filters also attenuate carriers adjacent or neighbored to said predetermined frequency bands, because notch filters for dynamic suppression of frequencies have weaker slopes, especially if there are many individual frequencies to be notched.